The problem of keeping a hose, tube or pipe work internally clean is a perennial problem. Where the hose or tube is used for example in the food industry or in a medical environment, it becomes critical that the lines remain clean. Similarly, in hydraulic and pneumatic lines internal contamination can cause breakdown and costly down time. There are many other situations in other industries which employ hose, tube, conduit or piping where internal cleaning is essential, or would result in substantial savings by eliminating replacement costs.
A very efficient known means of cleaning hose and tube is to force a compressible projectile, that has an outside diameter greater than the internal diameter of the hose or tube, therethrough under pressure. The projectile as it travels along the hose or tube thus removes particulate material from the internal wall. A number of projectiles can be repeatedly passed through lengths of the hose or tube under pressure to ensure that all contaminate matter has been removed. The usual means of effecting this cleaning operation is to place the projectile in a compressed air gun and then to operate a valve causing compressed air to flow through the gun and enter the tube via a nozzle that is coupled to the end of the hose or tube. The compressed air forces the projectile through the nozzle into and along the tubes to clean the interior of the pipe.
A problem with this type of equipment is that for the system to work satisfactorily, by ensuring that the projectile does not get stuck in the hose or tube, it is most important that there is no air loss between the gun and the tube. Since hose and tube comes in a variety of diameters and materials there is a need for a pneumatic gun that can be adapted simply for use over a range of hose products.
In commonly assigned U.S. Pat. No. 4,974,277 a hand held pneumatic gun is described, having an airway that is coupled to a source of compressed air, the airway communicating with an air chamber via a trigger valve. The gun includes a detachable breech that is supported in sealed engagement against the air chamber by a support ring pivotally secured to the body of the gun. The breech incorporates a nozzle that is secured to one end of a piece of hose or tube and a polymer projectile is placed into the breech to be forced by the air pressure through the hose or tube to clean the interior of the hose or tube.
Although the above hand held pneumatic gun was extremely well received and well adapted to its function, a number of problems have emerged during use of the gun. The present invention is concerned with a number of improvements to the gun which have been made with a view to overcoming these problems responsive to end-users requirements.
The present invention is also concerned with several improved types of projectile employed with the pneumatic gun.